Tendon repair surgery typically includes the reinforcement and rejoining of existing tendon tissue, and may include a graft of tendon, from the patient's own body or from another source, such as an animal. It is not unusual in this type of surgery for some portion of the tendon to be reinforced by suture that is sewn into the tendon, repeatedly entering and exiting as the suture extends lengthwise by way of a set of transverse loops. In a technique that is used in both rotator cuff and Achilles tendon repair, in particular where the tendon has ruptured near an anchor point, suture tape in a crossing pattern is used to perform that principal retaining function, acting to replace a portion of the tendon function. In rotator cuff surgery, with the use of round suture, knots are tied, which at the completion of surgery lie directly under the skin, potentially causing patient discomfort. Other problems, such as reinjury, persist. When suture that is not absorbable is used, the lack of elasticity in the suture can cause implanted tendon to tear if the patient flexes too quickly, for example while jumping, in the instance of an Achilles tendon repair. Moreover, permanent suture can cause a subtle disfigurement of the repaired joint and continuing discomfort.
When suture made of absorbable material is used, however, some absorbable material typically is absorbed before robust tissue ingrowth can fully occur. Accordingly, there is a window of vulnerability, when a good portion of the suture is reabsorbed, but the tissue is not in an adequately strong state to support the full strain of, for example, jumping. Many of the absorbable fibers used in partially absorbable sutures are absorbed over a period of about 4 to 6 months, which for many patients is not enough time for adequate recovery.
When reinjury occurs, an entire new surgery is warranted, with the attendant expense. Accordingly, it is very important that tendon repair be provided in a state which quickly becomes and remains, robust.